Unrestored 102 SD (Naval?)

[charlesp]

A measurement of the height of the flywheel centre may prove instructive.

[Collector Inspector]

Instructive? Height of flywheel this one (SD4726L3)is the same as my others within reach (SD6226L3 and SD9588L4) +/- 0.5mm.

B

[Beagle2]

Thanks for all the replies everyone.

Crank measurements:

My top crank measurements come up slightly under? If they were the same the flywheel would sit even higher (!). However, I have seen differences between cranks before. I have a Century crank, which is approx 4mm shorter overall.

18.82 - 14.4
33.19 - 28.0
41.11 - 37.5
8.16 - 9.8
12.43 - 11.3
7.41 - 6.9

The lower measurements seem to be the same

6.31 - 6.4
34.76 - 34.1

Flywheel measurement

Slightly lower, between 45.1mm and 45.5mm

Oysters pics:

"These are my two SDs, plus a pic of one now sold. Quite a variation between the three" - yes quite a bit!

I forgot to mention my SD has no locating 'dimple'. If I move my base plate up a bit, it looks very similar to Oyster's first pic. I imagine I'll have to somehow set the timing manually?

I seed no evidence of the crank-case being machined / altered. My crank-case doesn't have "Seagull" cast into it, so I imagine it is an earlier version.

The washer seems a like a bit of an later bodge. The inner diameter doesn't match. Furthermore, it is uneven and wobbles when the base-plate is installed above.

I'm hoping that I just have a particularly 'high' sitting flywheel.

[charlesp]

I meant the height of the one that has the washer - I'm wondering if the bashing around the rim may have flattened the dished top.

[Collector Inspector]

Well, lots of measuring above, who knows where it will sort out.

Classic questions and info this post..........love it

Regards

B

[Oyster 49]

Looking at that crankcase casting, it does not seem quite "right" if you know what I mean. There are differences in the detail of the casting. Could you actually have a pre SD pair of crankcases there? This is a picture of a SD upper crankcase half, spot the differences? The lack of "Seagull" cast into the case is intriguing

[Beagle2]

Hmmm. I don't know. Here are some more pictures. The cases certainly seem to match; maybe they were left over pre SD?

Maybe pre SD the crank was slightly different- hence con-rod bolts scraping on the inner crank-case?

[Charles uk]

There's another question for the SD registration form.

[Horsley-Anarak]

My SD is only about 300 away from yours, it is also an L3.

There is no seagull on the crankcae on mine.

Perhaps the 3 after the L means something, could be a different factory perhaps.

Does yours have the Skeg stamp?

H-A

[Beagle2]

Hi, yes mine has a skeg stamp: "CIESS <- G 232", gearbox stamped 35, gearbox cover stamped 34.

I'm actually replacing this box with one from Oyster. The gear pinion was badly chipped

[Beagle2]

I meant the height of the one that has the washer - I'm wondering if the bashing around the rim may have flattened the dished top.

Sorry Charles, missed your post. Height of flywheel center is 60.1mm

[Hugz]

My early (125) also has seagull on the case.

[Collector Inspector]

Is that a washer/spacer in that pic Huggy?

OR

Is it the split bush end.

There is a split bush in the casting of the backing plate, it can be moved in or out to maybe make a "Base Height adjustment"?

Just a thought.

B

[Collector Inspector]

I Hear Silence

B

[Hugz]

No washer just the..... BUSH......